Add ability to manipulate scheme objects

This is step 0 in a plan to use the scheme evaluator to evaluate Idris
expressions at compile time. As a proof of concept, I've got this
working for a toy language here: https://github.com/edwinb/SchemeEval

We won't be able to do anything interesting with this in Idris itself
until the next release because it involves updating the bootstrap code
and adding the ability to pass 'Integer' to foreign calls, which really
should have been allowed anyway since it's for a backend to decide what
it can cope with, not Idris itself.

src/Compiler/CompileExpr.idr

@@ -575,6 +575,7 @@ data NArgs : Type where
      NPtr : NArgs
      NGCPtr : NArgs
      NBuffer : NArgs
+     NForeignObj : NArgs
      NIORes : Closure [] -> NArgs
 
 getPArgs : {auto c : Ref Ctxt Defs} ->
@@ -611,6 +612,7 @@ getNArgs defs (NS _ (UN "AnyPtr")) [] = pure NPtr
 getNArgs defs (NS _ (UN "GCPtr")) [arg] = pure NGCPtr
 getNArgs defs (NS _ (UN "GCAnyPtr")) [] = pure NGCPtr
 getNArgs defs (NS _ (UN "Buffer")) [] = pure NBuffer
+getNArgs defs (NS _ (UN "ForeignObj")) [] = pure NForeignObj
 getNArgs defs (NS _ (UN "Unit")) [] = pure NUnit
 getNArgs defs (NS _ (UN "Struct")) [n, args]
     = do NPrimVal _ (Str n') <- evalClosure defs n
@@ -621,6 +623,7 @@ getNArgs defs n args = pure $ User n args
 nfToCFType : {auto c : Ref Ctxt Defs} ->
              FC -> (inStruct : Bool) -> NF [] -> Core CFType
 nfToCFType _ _ (NPrimVal _ IntType) = pure CFInt
+nfToCFType _ _ (NPrimVal _ IntegerType) = pure CFInteger
 nfToCFType _ _ (NPrimVal _ Bits8Type) = pure CFUnsigned8
 nfToCFType _ _ (NPrimVal _ Bits16Type) = pure CFUnsigned16
 nfToCFType _ _ (NPrimVal _ Bits32Type) = pure CFUnsigned32
@@ -662,6 +665,7 @@ nfToCFType _ s (NTCon fc n_in _ _ args)
               NPtr => pure CFPtr
               NGCPtr => pure CFGCPtr
               NBuffer => pure CFBuffer
+              NForeignObj => pure CFForeignObj
               NIORes uarg =>
                 do narg <- evalClosure defs uarg
                    carg <- nfToCFType fc s narg

src/Core/CompileExpr.idr

@@ -153,6 +153,7 @@ public export
 data CFType : Type where
      CFUnit : CFType
      CFInt : CFType
+     CFInteger : CFType
      CFInt8 : CFType
      CFInt16 : CFType
      CFInt32 : CFType
@@ -167,6 +168,7 @@ data CFType : Type where
      CFPtr : CFType
      CFGCPtr : CFType
      CFBuffer : CFType
+     CFForeignObj : CFType
      CFWorld : CFType
      CFFun : CFType -> CFType -> CFType
      CFIORes : CFType -> CFType
@@ -350,6 +352,7 @@ export
 Show CFType where
   show CFUnit = "Unit"
   show CFInt = "Int"
+  show CFInteger = "Integer"
   show CFInt8 = "Int_8"
   show CFInt16 = "Int_16"
   show CFInt32 = "Int_32"
@@ -364,6 +367,7 @@ Show CFType where
   show CFPtr = "Ptr"
   show CFGCPtr = "GCPtr"
   show CFBuffer = "Buffer"
+  show CFForeignObj = "ForeignObj"
   show CFWorld = "%World"
   show (CFFun s t) = show s ++ " -> " ++ show t
   show (CFIORes t) = "IORes " ++ show t

src/Core/Hash.idr

@@ -235,6 +235,10 @@ Hashable CFType where
       h `hashWithSalt` 19
     CFInt64 =>
       h `hashWithSalt` 20
+    CFForeignObj =>
+      h `hashWithSalt` 21
+    CFInteger =>
+      h `hashWithSalt` 22
 
 export
 Hashable Constant where

src/Core/TTC.idr

@@ -785,6 +785,8 @@ TTC CFType where
   toBuf b CFInt16 = tag 18
   toBuf b CFInt32 = tag 19
   toBuf b CFInt64 = tag 20
+  toBuf b CFForeignObj = tag 21
+  toBuf b CFInteger = tag 22
 
   fromBuf b
       = case !getTag of
@@ -809,6 +811,8 @@ TTC CFType where
              18 => pure CFInt16
              19 => pure CFInt32
              20 => pure CFInt64
+             21 => pure CFForeignObj
+             22 => pure CFInteger
              _ => corrupt "CFType"
 
 export

support/chez/support.ss

@@ -481,3 +481,70 @@
         (when x
           (((cdr x) (car x)) 'erased)
           (run))))))
+
+;; For creating and reading back scheme objects
+
+; read a scheme string and evaluate it, returning 'Just result' on success
+; TODO: catch exception!
+(define (blodwen-eval-scheme str)
+  (box (eval (read (open-input-string str))))) ; box == Just
+
+(define (blodwen-eval-okay obj)
+  (if (null? obj)
+      0
+      1))
+
+(define (blodwen-get-eval-result obj)
+  (unbox obj))
+
+(define (blodwen-debug-scheme obj)
+  (display obj) (newline))
+
+(define (blodwen-is-number obj)
+  (if (number? obj) 1 0))
+
+(define (blodwen-is-integer obj)
+  (if (integer? obj) 1 0))
+
+(define (blodwen-is-float obj)
+  (if (flonum? obj) 1 0))
+
+(define (blodwen-is-char obj)
+  (if (char? obj) 1 0))
+
+(define (blodwen-is-string obj)
+  (if (string? obj) 1 0))
+
+(define (blodwen-is-procedure obj)
+  (if (procedure? obj) 1 0))
+
+(define (blodwen-is-symbol obj)
+  (if (symbol? obj) 1 0))
+
+(define (blodwen-is-vector obj)
+  (if (vector? obj) 1 0))
+
+(define (blodwen-is-nil obj)
+  (if (null? obj) 1 0))
+
+(define (blodwen-is-pair obj)
+  (if (pair? obj) 1 0))
+
+(define (blodwen-make-symbol str)
+  (string->symbol str))
+
+; The below rely on checking that the objects are the right type first.
+
+(define (blodwen-vector-ref obj i)
+  (vector-ref obj i))
+
+(define (blodwen-vector-length obj)
+  (vector-length obj))
+
+(define (blodwen-apply obj arg)
+  (obj arg))
+
+(define (blodwen-read-symbol sym)
+  (symbol->string sym))
+
+(define (blodwen-id x) x)